Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
LICENSEE: MSD, INC
SITE: STRUTHERS-DUNN EN NUMBER:30322
DOCKET: EVENT DATE: 04-19-96
RX TYPE: EVENT TIME: 00:00
VENDORS: NOTIFY DATE: 04-19-96
EMERGENCY CLASS: N/A REGION: 2 STATE: SC TIME: 12:03
OPS OFFICER: BOB STRANSKY
10 CFR SECTION: CDEF 21.21(b)(2) DEFECTS/NONCOMPLIANCE
10 CFR PART 21 REPORT - INCORRECT COILS INSTALLED IN TIME DELAY
RELAYS
THE FOLLOWING IS TEXT EXCERPTED FROM A FACSIMILE SUBMITTED BY THE
VENDOR:
"IT HAS COME TO OUR ATTENTION THAT A QUANTITY OF STRUTHERS-DUNN
TYPE 236ABX135NE TIME DELAY RELAYS BUILT IN 1983 HAVE INCORRECT
COILS IN THEM. SPECIFICALLY, THE AFFECTED RELAYS CONTAIN 39 GAUGE
COILS; THEY SHOULD HAVE 43 GAUGE. AS A RESULT, THE COILS CONSUME
SEVERAL TIMES THE REQUIRED POWER WHICH IS DISSIPATED AS HEAT, AND
UPON PROLONGED ENERGIZATION MAY OVERHEAT TO THE POINT OF
SELF-DESTRUCTION. WE HAVE ONE SUCH OCCURRENCE TO DATE.
WE BELIEVE THE DEFECT WAS CAUSED BY PERSON OR PERSONS WHO RELIED
ON MEMORY RATHER THAN DOCUMENTATION WHEN BUILDING THESE DEVICES.
THEY WERE INTENDED FOR USE ON 125-VOLT DC CIRCUITS; THE COILS
INSTALLED ARE THOSE NORMALLY USED ON 120-VOLT AC. SINCE THE
RELAYS WOULD FUNCTION PROPERLY FOR BRIEF PERIODS, THE DEFECT WAS
OBVIOUSLY OVERLOOKED.
TO DATE, WE HAVE FOUND NINE RELAYS AS DESCRIBED, ALL AT GEORGIA
POWER'S PLANT HATCH. ALL ARE DATE CODED 8335 WHICH INDICATES
THEY WERE BUILT IN THE 35TH WEEK OF 1983. WE ARE OF THE OPINION
THIS WAS THE ONLY TIME THIS OCCURRED, BUT THERE IS NO WAY TO
PROVE IT ... FORTUNATELY, THESE RELAYS' COILS ARE CLEARLY MARKED,
AND VERIFICATION OF CORRECT COIL GAUGE CAN BE ACCOMPLISHED WITH A
VISUAL INSPECTION ... AGAIN, WE BELIEVE PLANT HATCH HAS THE ONLY
ONES, BUT WE CANNOT BE CERTAIN."
THE ASSETS OF STRUTHERS-DUNN WERE PURCHASED IN 1990 BY MSD, INC.
